Download High School Infectious Disease Virtual Field Trip

INFECTIOUS DISEASE:
Evolving Challenges to Human Health
High School Virtual Field Trip
Overview
This activity guides students in an exploration of the online exhibit Infectious Disease: Evolving
Challenges to Human Health. Students will explore the question:
What strategies and challenges exist to effectively control infectious disease
around the world?
The class will discuss the types of decisions that the evidence gathered today could support, as
well as the uncertainty associated with the evidence. For example:
•
•
•
•
What evidence is used to determine the status of infectious diseases?
What are the biological mechanisms that contribute to the spread of infectious disease?
How do sociopolitical (geographic, economic, cultural) forces contribute to the spread of
infectious disease?
What are the main challenges involved with controlling infectious disease in both
developing and industrialized countries?
Directions
1. Direct all students to explore the sections Rapid Evolution, Where are They?, Global
Distribution of Disease, and Public Health. Students may work individually or in groups and may
visit the sections in any order. They should use the appropriate worksheet to guide their
exploration.
2. Students should then be assigned to one of three “expert groups” and explore the rest of the
exhibit using this particular focus.
• Public Health: What strategies and challenges exist to effectively control infectious
disease around the world?
• Therapeutic Drugs: What strategies and challenges exist to effectively control infectious
disease around the world?
• Vaccines: What strategies and challenges exist to effectively control infectious disease
around the world?
3. Once students have explored the exhibit they should remain in their expert groups to answer
the questions on the discussion worksheet.
4. Lead a whole class discussion, allowing each group to report out the information they have
gathered and to discuss answers.
5. The Disease Spread Activity can be used as an extension activity.
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Explore the sections Rapid Evolution, Where Are They?, Public Health, and Global Distribution
of Disease. The following questions will guide you through the sections.
Rapid Evolution
1. Watch the Rapid Evolution video and pay close attention to the graph as time passes. Which
strain of bacteria is resistant to more than one drug? Why do you think this?
2. If a bacterium divides every half hour, how many bacteria are there...
• At two hours (4 generations)?
• At four hours (8 generations)?
• At eight hours (16 generations)?
• What if they continued reproducing for 24 hours (48 generations)?
3. What two factors combined lead to microbial evolution?
+
= Evolution
4. Antibiotics can kill bacteria, yet bacteria may continue to spread. Why do you think this might
be?
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Where Are They?
Explore the interactive to discover how bacteria, viruses, fungi and parasites differ and
complete the following chart:
Source
Fungus
Parasite
Bacteria
Virus
Associated
Disease
Disease Location
on Body
Pathogenic?
Commensal?
Harmless?
Unknown?
Global Distribution of Disease
1. Describe where cholera is most prevalent. What do you think the relationship is between
cholera prevalence and access to sanitation? What do you think the relationship is between
cholera prevalence and access to clean drinking water?
2. Choose another disease and describe where it is most widespread.
Disease
Where is it most widespread?
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Public Health
1. Not all countries enjoy the same level of public health as the U.S.
How many people worldwide lack clean water?
How many people worldwide lack basic sanitation?
2. Study “The Impact of Public Health” graphs and note that both life expectancy (blue) and
mortality rates (yellow) have improved in the United States from 1900 to 2000. Life
expectancy at birth has increased (people live longer) and mortality rates have decreased
(less people are dying from infectious diseases).
Gather data on the mortality rate and the change in mortality rate:
Mortality Rate
Year Range Change in Mortality Rate
Year
1900 _________ deaths per
100,000 people
1940
_________ deaths per
100,000 people
1900 – 1940
_________ deaths per
100,000 people
1980
_________ deaths per
100,000 people
1940 – 1980
_________ deaths per
100,000 people
3. Based on the data you gathered in the previous question, did mortality rates drop most
before or after antibiotics and vaccines were first used (around 1940)? (circle one)
Before antibiotics and vaccines (1900-1940)
After antibiotics and vaccines (1940-1980)
4. List two public health measures that resulted in improved life expectancy in the U.S. before
1940. (Many answers are possible.)
5. What disease caused a large “spike” in the graphs prior to 1920?
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Public Health Expert Group
Your team will gather in-depth information on how well public health measures can effectively
prevent the spread of disease. The information you gather on these topics will be vital for the
group discussion, which will focus on:
What strategies and challenges exist to effectively control infectious disease around the world?
Explore the following sections and give examples where public health measures have been used
successfully and where challenges still exist.
Vector Control and Malaria
Explore how effective public health measures, such as bed nets and indoor spraying, can be in
controlling the spread of malaria by themselves and in combination with other measures.
Successes:
Challenges:
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Antiretrovirals and the HIV Pandemic
Watch both HIV/AIDS videos and describe how effective public health measures have been in
controlling the spread of the HIV virus.
Successes:
Challenges:
6
Therapeutic Drugs Expert Group
Your team will gather in-depth information on how well therapeutic drugs can effectively
prevent the spread of disease. The information you gather on these topics will be vital for the
group discussion, which will focus on:
What strategies and challenges exist to effectively control infectious disease around the world?
Explore the following sections and give examples where therapeutic have been used
successfully and where challenges still exist:
Antibiotics and Emerging Drug Resistance
Using the exhibit and interactive sliding screen, explore how effective antibiotics can be in
preventing the spread of bacterial diseases.
Successes:
Challenges:
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Antiretrovirals and the HIV Pandemic
Watch both HIV/AIDS videos and describe how effective antiretroviral drugs can be in
controlling the spread of the HIV virus.
Successes:
Challenges:
8
Vector Control and Malaria
Explore how effective therapeutic drugs can be in controlling the spread of malaria by
themselves and in combination with other measures.
Successes:
Challenges:
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Vaccines Expert Group
Your team will gather in-depth information on how well vaccines can effectively prevent the
spread of disease. The information you gather on these topics will be vital for the group
discussion, which will focus on:
What strategies and challenges exist to effectively control infectious disease around the world?
Explore the following sections and give examples where vaccines have been used successfully
and where challenges still exist:
Vaccines and Human Immunity
Using the exhibit and interactive table display, explore how effective vaccines can be in
preventing the spread of disease.
Successes:
Challenges:
10
Antiretrovirals and the HIV Pandemic
Watch both HIV/AIDS videos and describe how effective vaccines can be in controlling the
spread of the HIV virus.
Successes:
Challenges:
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Expert Summary
Answer the questions for your expert group and brainstorm responses to the “all groups
answer” questions before sharing your findings with your classmates.
Public Health Expert Group
1. What are some of the specific public health measures used to prevent the spread of disease?
2. Give three examples where public health measures can be effective tools in preventing the
spread of disease.
3. Describe three challenges for using public health measures in preventing the spread of
disease.
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Vaccine Expert Group
1. What are some of the specific vaccine programs used to prevent the spread of disease?
2. Give three examples where vaccines have been effective tools in preventing the spread of
disease.
3. Describe three challenges for using vaccines in preventing the spread of disease.
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Therapeutic Drugs Expert Group
1. What are some of the specific therapeutic drugs used to prevent the spread of disease?
2. Give three examples where therapeutic drugs can be effective tools in preventing the spread
of disease.
3. Describe three challenges for using therapeutic drug in preventing the spread of disease.
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All Groups Answer
1. Why is an understanding of evolution so important to addressing infectious disease?
2. What ideas can you come up with that might help address the major scientific, medical, and
public health challenges to treating infectious diseases throughout the world?
BONUS: Give one example where global warming has already had an impact on human health.
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Simulating the Spread of an Infectious Disease
Introduction
From bubonic plague to AIDS to the Guinea worm parasite, scientists and public health officials
have struggled to understand and contain the spread of infectious diseases. Using simple
reagents, students can simulate the spread of a simple imaginary disease in order to explore
some factors that affect the rate of infection, the challenges of epidemiology, and measures
which can help prevent the spread of disease.
Materials
• Test tube and dropper for each participant
• Test tube lids
• Distilled water
• 0.1 molar NaOH
• pH 7.0 buffer solution
• Phenolphthalein solution, dissolved in alcohol and diluted in water (pH indicator)
Procedure
1. Prepare the test tubes prior to the activity. Fill one tube halfway with 0.1 molar NaOH and
one with the phenolphthalein solution; fill the rest of the tubes halfway with distilled water. If
you have a large group (35 or more) you may want to begin with two test tubes containing
NaOH.
2. Explain to students that they are going to model the transmission of a disease by exchanging
some of their test tube’s contents with that of other participants. Mention that one of the test
tubes is "infected" with an imaginary infectious disease.
2. Distribute prepared test tubes and droppers to the class. Make a mental note of who
receives the test tube containing NaOH. Keep the test tube with the phenolphthalein.
3. Have participants walk around the room with their test tubes. When you say "Stop!", each
participant should use a dropper to trade a drop of fluid with the person nearest them. Repeat
until at least three trades have occurred.
4. Now it's time to test for the imaginary infection. Put a drop of phenolphthalein in each test
tube. If the fluid turns pink, the cup is "infected" with NaOH. The final number of "infected" test
tubes will vary depending on (1) the number of trades and (2) how many trades occur between
two already infected tubes.
CAUTION: Sodium hydroxide (NaOH) and phenolphthalein can irritate the eyes and skin. Alert
students to avoid spilling and warn them to NEVER drink what is in the test tube.
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Tracing the Source of Infection
Now that a portion of the group has been "infected," put students in the role of
epidemiologists. Their challenge is to collect data that will help them trace the path of the
epidemic and locate the original carriers.
As a group, use the data to try to deduce which individual was the original carrier of the
disease. Why might it be important to locate the source of infection? What difficulties arise in
trying to collect and interpret data? Note that the simulated disease has a 100% rate of
infection that appears immediately under testing. Some infections, such as AIDS and chicken
pox, can remain dormant in the body for a long time. Others, such as Ebola, kill the host rapidly.
How might each of these factors affect the spread of disease and the ability to identify carriers?
A possible method to find "patient zero" is to have each participant write his or her name on
the board and underneath it the names of participants with whom he or she exchanged fluids in
the order in which the exchanges occurred. Then, as a group, highlight the names of the
currently "infected" people.
The sample chart shows one example of how to trace the infection (bolded names are
infected). Participants who "test positive" and find that everyone with whom they traded also
tested positive may be original carriers of the disease (Cal, Dee, Gib, and Hal in this example). It
is likely that there will be several candidates for "patient zero." Cross-checking the history of
each contact can narrow the field, but probably not to less than two candidates. (For example,
here, Cal and Dee can be eliminated as "patient zero" because their first contacts, Bob and Ed,
did not infect their own second contacts, Fran and Ilsa; either Gib or Hal, however, could be
"patient zero.") If participants are unable to reach a clear conclusion, the exercise will raise
useful questions about the challenges facing real epidemiologists as they try to trace the
sources of an infection.
Sample Chart Tracing Infection
Exchange 1
Exchange 2
Exchange 3
Ann
Fran
Jo
Gib
Bob
Cal
Fran
Dee
Cal
Bob
Gib
Ed
Dee
Ed
Hal
Bob
Ed
Dee
Ilsa
Cal
Fran
Ann
Bob
Jo
Source: This activity is based in part on an activity presented at:
www.pbs.org/wgbh/aso/resources/guide/medact4index.html.
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Gib
Hal
Cal
Ann
Hal
Gib
Dee
Lin
etc…
etc…
etc…
etc…
Discussion
Lead a class discussion about measures for preventing the spread of disease.
First, discuss how rapid and constant evolution challenges our main defenses against infectious
diseases, which include
• public health measures that minimize exposure to disease-causing organisms;
• immunity, whether gained by infection or vaccination; and
• therapeutic drugs used to treat infections.
Discuss these defenses, then brainstorm and demonstrate how these defenses could be
enacted in the context of the activity.
1. Public Health: Minimizing or eliminating exposure to disease agents through public health
measures can greatly diminish the impact of a disease outbreak. Some examples that represent
public health measures:
• Put a cap on your test tube
• Isolate yourself so that you are not near anyone else
The cap represents measures such as bed nets or condoms, which prevent exposure to disease
causing agents. Isolating yourself is the same as a quarantine, which is often used to isolate
disease carrying individuals during an outbreak.
2. Immunity: Vaccines provide immunity for an individual against a disease, even after
exposure. Using the test tube with the buffer solution, add a couple of drops of the
phenolphthalein indicator, followed by a couple of drops of the NaOH solution. While there
might be a quick flash of pink when the drops of NaOH hit the test tube solution, the color
should quickly return to clear. The buffer is acting to neutralize the NaOH.
3. Therapeutic drugs: Drugs can be an effective means for treating a disease after exposure.
Take a test tube that has tested positive by turning pink and add a few drops of the buffer. In
this case, the buffer will neutralize the solution and turn the color back to clear, thus
eliminating the infection.
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Infectious Disease Terms Glossary
Term
Commensalism
Endemic Disease
Epidemic
Definition
An unequal relationship in which one species derives benefit without
harming the other.
A native disease that exists continuously in a geographic region.
A sudden and simultaneous outbreak or increase in the number of
cases of a disease in a community.
Eradicate/Eradication To eliminate completely (a disease).
Organisms in which smaller organisms or viruses live, feed, and
Host
reproduce.
A branch of the National Academies with the mission to serve as
adviser to the nation to improve health. The Institute provides
IOM (Institute of
unbiased, evidence-based, and authoritative information and advice
Medicine)
concerning health and science policy to policy-makers, professionals,
leaders in every sector of society, and the public at large.
Total number of deaths in a population attributable to a particular
Mortality Rate
disease.
Related to the nasopharynx, which is the upper part of the pharynx
Nasopharyngeal
(throat) behind the nose.
Non-endemic
Pandemic
Pathogenic
Public Health
Measure
Therapeutic Drug
A disease that is not native to and contained within a certain
geographic region.
A disease afflicting an increased proportion of the population over a
wide geographic area (often worldwide).
The ability of microbes to cause disease.
Any number of steps taken in a community to contain, prohibit, and
eliminate the spread of an infectious disease. These range from the use
of vaccinations on a large scale, to chlorination of water, to the use of
bed nets among many other methods.
Any drug taken to help cure a disease or symptoms associated with it.
Vaccines
Vaccines present a pathogenic organism’s signature molecules to the
immune system. A vaccine stimulates the natural immune response,
creating antibodies and a chemical memory of the infection without
the danger of an actual infection. The chemical memory helps protect
us if we are ever exposed to the pathogen in the future.
Vector
An animal that transmits infectious agents from one host to another,
usually a biting or piercing arthropod like the tick, mosquito, or fly.
Infectious agents can be conveyed mechanically by simple contact or
biologically whereby the parasite develops in the vector.
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This activity addresses the following Next Generation Science Standards and Common Core
State Standards for high schools.
Next Generation Science Standards
Standards
• HS-LS2 Ecosystems: Interactions, Energy,
and Dynamics: HS-LS2-1, HS-LS2-6
• HS-LS3 Heredity: Inheritance and Variation
of Traits: HS-LS3-2
• HS-LS4 Biological Evolution: Unity and
Diversity: HS-LS4-2, HS-LS4-4, HS-LS4-5
• HS-ETS1 Engineering Design: HS-ETS1-1
Science and Engineering Practices
• Asking questions (for science) and defining
problems (for engineering)
• Using mathematics and computational
thinking
• Constructing explanations (for science) and
designing solutions (for engineering)
• Engaging in argument from evidence
Crosscutting Concepts
• Cause and effect: Mechanism and
explanation
• Scale, proportion, and quantity
• Stability and change
Common Core State Standards
ELA/Literacy
• Literacy in Science and Technical Subjects
(Grades 9 and 10): RST.9-10.8
• Literacy in Science and Technical Subjects
(Grades 11 and 12): RST.11-12.1, RST.1112.7, RST.11-12.8, RST.11-12.9
• Speaking and Listening (Grades 11 and 12):
SL.11-12.4
• Writing (History/Social Studies, Science, and
Technical Subjects): WHST.9-12.1, WHST.912.2, WHST.9-12.9
Mathematics
• Standards for Mathematical Practice: MP.2,
MP.4
• Number and Quantity – Quantities:
HSN.Q.A.1, HSN.Q.A.2, HSN.Q.A.3
• Statistics & Probability – Interpreting
Categorical & Quantitative Data: HSS.ID.A.1
• Statistics & Probability – Making Inferences
& Justifying Conclusions: HSS.IC.A.1,
HSS.IC.B.6
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